A possible solution might be to look at the SZE emission at frequencies higher than the THz, where it should reach its maximum, depending on the properties of the electrons population. For example, it has been suggested that the Hard X-ray band can be good to distinguish between the ICS emission of the non-thermal electrons and the bremsstrahlung of the high temperature thermal gas, because the efficiency of the ICS process is much higher than the bremsstrahlung one [1]}. In order to check this possibility, in Fig.REF  we compare the thermal and non-thermal SZE spectra calculated at high frequencies, from the THz until \(10^{19}\)  Hz (corresponding to a photon energy of \(\sim 40\)  keV), for values of the gas temperature inside the cavity of 1000 and 1500 keV.
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